Mineral material, for example rock, is gained from the earth for crushing by exploding or excavating. The rock can also be natural rock and gravel or construction waste. Mobile crushers and stationary crushing applications are used in crushing. An excavator or wheeled loader loads the material to be crushed into the crusher's feed hopper from where the material to be crushed may fall in a jaw of a crusher or a feeder moves the rock material towards the crusher. The material to be crushed may also be recyclable material such as concrete, bricks, or asphalt.
A conveyor often increases the length, width and/or height of the plant in a movable mineral material processing plant. Therefore the conveyor may be positioned in another location during operation than during transport or service of the plant. Moving the conveyor from the operation position of the plant to the transport or service position of the plant requires in some cases detaching of the conveyor from place. Additionally the conveyor is fixed to the plant for the transport. In many cases the entire conveyor must be moved from its location, for example in order to keep the conveyor inside transport dimensions (height, width, length) which are allowed or require a permission in road traffic.
In some known mineral material processing plants a crusher/screen is fed by a single part conveyor which is moved to a transport/service position by moving the conveyor towards a feeding end and downwards. A known screen is supported by telescopic operating legs on a frame of a processing plant. Another known screen is supported to the frame of the processing plant by pivoted legs which together with the screen and the frame form a four-bar linkage.
Moving mechanisms used for the moving of the conveyor are heavy and expensive constructions. The moving of the conveyor away from the crusher requires space at the feeding end of the plant which may be problematic if the plant in question is a mobile crushing plant which is operating in a process of several plants and a feeding machine is close. The plant must then be moved before service. Sliding mechanisms and telescopic operating legs are used for longitudinal moving of the conveyor in the plant. The sliding mechanisms tolerate poorly dirty circumstances and are sensitive with respect to production inaccuracy.
In a known movable crushing and screening plant the material which is crushed in a crusher is circulated by conveyors in a closed loop from the crusher to a screen. The overs of the screen is guided to the crusher. The product passing through the screen can be guided to further processing in the same plant or another plant which processes mineral material, or to a pile. A long single part conveyor is used in this closed loop plant for feeding the screen which conveyor is moved to a transport position by cylinder operations. The long conveyor which is feeding the screen is at side of the crusher what increases transport width and causes that when the screen is fed the material has to be moved sideways from a main conveyor to a feed conveyor for example by a vibration chute or hopper. Then the process includes an extra wearing part (vibration chute, hopper) and the material arrives to the screen from a side direction wherein spreading of the material evenly on the screen is problematic. Alternatively the plant must include an expensive, heavy, and often unreliable moving mechanism by which the conveyor can be moved off the crusher for transport and service of the crusher. Alternatively the conveyor must be lifted by a separate hoist which must be brought beside the plant which is expensive and time consuming.
Publication U.S. Pat. No. 8,020,691 B2 shows a first belt conveyor by which material is lifted onto a second belt conveyor taking advantage of the centrifugal force.
FIG. 12 shows a known centrifugal conveyor 210 which lifts material onto an upper conveyor 220. The upper conveyor feeds a screen 230. A conveyor belt 211 of the centrifugal conveyor is supported at sides to rotate around two idler rollers 212. The upper conveyor belt of the conveyor 220 is moved also by the same idler rollers. The conveyor belt 211 of the centrifugal conveyor circulates via an upper idler drum 213 and returns to the arrival direction after a lower idler drum 214. The centrifugal conveyor pivots open around a pivot 215 for feeding material from the conveyor belt before the upper conveyor what is shown by dashed lines.
An object of the invention is to avoid or at least reduce problems present in connection with prior art. An object of the invention is to provide new technical alternatives. An object of the invention is to enhance serviceability of a mineral material processing plant. An object of the invention is to enhance operation reliability, usability and transportability of a mineral material processing plant. An object of the invention is to simplify a mineral material processing plant. An object of the invention is to enhance processing of mineral material, for example shorten the shutdown time in connection with service.